Fire Emblem Heroes Guide: 20 Crucial Tips & Tricks You Need To Know

If you have any low-level units you want to rank up without grinding, the 'Level Up' option in the Allies menu will allow you to quickly ascend a character using collected Shards and Crystals. You will need matching-colour Shards or Crystals for the Hero you wish to boost, although you may also collect 'Universal Shards' which work on Heroes of any colour.

Down at the bottom of the 'Allies' tab is a button labelled 'Advanced Growth' - this features two more advanced options for increasing the power of your Heroes.

'Unlock Potential' allows you to upgrade a Hero’s star rating. The Hero in question must be at least level 20 and you will have to spend Badges (or Great Badges) and Hero Feathers. The Hero will be reset to level one, but will retain their unlocked skills and earned SP. Upgrading a character’s star rating will usually allow them to learn additional skills.

'Merge Allies' allows you to combine two duplicate Heroes, losing one to increase the stats and SP of the other. However, if the Hero you are destroying has a lower star rating, the remaining one will only gain SP.

Additionally, if you later upgrade the star rating of a unit, it will lose any stat bonuses that were granted. As a result, it may often be a better idea to keep two copies of a strong unit. Similarly, you may find it more worthwhile to 'Send Home' a weak spare unit for Hero Feathers, rather than merging it for a small SP gain.